Method of strengthening foundation piling



Nov. 26, 1968 K, B. LINDSEY ETAL 3,

METHOD OF STRENGTHENING FOUNDATION FILING 5 Sheets-Sheet 1 Filed Oct. 3, 1966 WATER lllIillll MUD ROCK

IN VE NTORS KENNETH B. LINDSEY GARVIN W. COOPER WILLIAM A. PEARCE ATTORNEY Nov. 26, 1968 K. B. LINDSEY ETAL. 3,412,565

METHOD O F STRENGTHENING FOUNDATION FILING Filed Oct. 5, 1966 I5 Sheets-Sheet 2 42 WATER MUD ROCK

IN VE N TORS KENNETH B. LINDSEY GARV/N W. COOPER WILLIAM A. PEARCE Nov. 26, 1968 K. B. LINDSEY ETAL 3,412,565

METHOD OF STRENGTHENING FOUNDATION FILING Filed Oct. 3, 1966 I5 Sheets-Sheet 5 IN VEN TORS KENNETH B. LINDSEY GARV/N W COOPER WILLIAM A. PEARCE ATTORNEY 3,412,565 METHOD OF STRENGTHENING FOUNDATION PILING Kenneth B. Lindsey, Houston, Garvin W. Cooper, Pasadena, and William A. Pearce, Houston, Tex., assignors to Continental Oil Company, Ponca City, Okla, a corporation of Delaware Filed Oct. 3, 1966, Ser. No. 583,583 9 Claims. (Cl. 61-535) ABSTRACT OF THE DISCLOSURE A method for reinforcing foundation piling which are positioned in the ground. Said method comprises positioning a reinforcing member inside the pile at a point of localized stress and rigidly securing said reinforcing member to the inside of said pile by expanding the reinforcing member into frictional engagement with the interior wall of said pile or by securing by chemical or mechanical means.

This invention relates to a method of strengthening cylindrical tubular foundation piling for offshore drilling operations and other applications wherein foundation piling are subjected to localized stresses.

The drilling of offshore wells requires the use of foundation piling which are capable of withstanding severe stress. The greatest stress on piling is imposed by bending and shearing at the mud line; and, to increase the strength through this zone, it is necessary to add reinforcing material to the piling. Heavier wall pile has been used to some extent; but this approach is self limiting as the increasing weight becomes more difficult to handle, the cost rises rapidly and sufficient strength cannot be obtained for difficult applications. Another method used is to add reinforcing when fabricating the piling through the section of pile that is calculated to be located at the mud line at final driving. This method is not too satisfactory as the required resistance to driving may develop above or below the calculated point thereby resulting in a pile having the increased strength located at a point different from that Where maximum stress is applied.

An object of this invention is to provide a method of reinforcing piling at the desired point of stress.

Another object is to provide a method of reinforcing piling which have been previously positioned.

A further object is to provide a method of reinforcing piling which results in piling of suflicient strength but which is light weight and inexpensive.

The invention features a method of strengthening a pile by positioning a tubular reinforcing member inside the pile and expanding the member into frictional engagement at the desired level inside said pile. The reinforcing member can also be a double-walled pipe with the two walls connected by metal webbing. The tubular reinforcing member can be expanded by drawing an expander mandrel through the reinforcing member by means of a hydraulic or pneumatic piston, or it may be expanded by means of a tube roller powered through a drive shaft from the surface.

Another feature of this invention is a method of strengthening a pile by positioning a reinforcing member at the desired level inside said pile. The reinforcing member can be rigidly secured in place by cementing with a high-tensile strength epoxy resin cement; such as, maleic anhydride reacted with the condensation product of epichlorohydrin and bis-phenol A, resin cement or glue or by mechanical means; such as, lock screws, welding or slip dogs.

A further feature of this invention is a method of strengthening piling by placing a plurality of Wedgenited States Fatent G ice shaped sections of sufficient length within the pile and at the desired position so as to line the interior wall of the pile. A second plurality of wedge-shaped sections is positioned within the first placed sections so as to spread the first placed sections into frictional engagement with the interior wall of the piling upon applying outward pressure to the second placed sections.

If the requisite strength is not developed in the pile by the addition of a sir 1 gle layer of steel, successive layers can be added, using the method of this invention, until the needed strength is developed.

The foregoing and other objects, features and advantages of the invention will become apparent upon full consideration of the following detailed description and accompanying drawings in which:

FIGURE 1 is a cross-sectional view of a pile in place and showing a reinforcing member in cross-sectional view and means for expanding said reinforcing member in full view.

FIGURE 2 is a cross-sectional view of a pile and showing a reinforcing member in cross-sectional view and means for expanding said reinforcing member in full view.

FIGURES 3a to 3d are a series of top views of piling having different types of reinforcing members placed therein.

FIGURES 4a to 40 are a series of partial views showing different means for rigidly securing a r inforcing member to the interior wall of a pile.

Referring to the drawings in detail and particularly FIGURE 1, a pile 10 is shown having a reinforcing member 12 located therein. Expander mandrel 14 is positioned inside reinforcing member 12 and is shown in a partially advanced position to show reinforcing member 12 expanded to form expanded reinforcing member 30 and the portion of expanded reinforcing member 30 further expanded to form frictionally engaged member 32. Hold down plate 16 is shown in position and holding down reinforcing member 12. Hold down plate 16 forms the bottom portion of a pressure chamber 15 and has a pressure seal 34 positioned around a piston 18. A pressure inlet 20 is connected to pressure chamber 15 and to a pump 26. A pressure outlet 22 is connected to pressure chamber 15 and to a sump 28. A support member 24 is connected to pressure chamber 15 and to a derrick or crane (not shown).

In FIGURE 2 a tube roller 46 is positioned inside reinforcing member 12. Reinforcing member 12 is positioned inside pile 10. A packer 36 holds down reinforcing member 12 and has a pressure inlet 38 and a bearing 34. A rotary drive shaft extension 40 is connected at one end to a rotary drive means (not shown) and to a rotary drive shaft 41 by a collar 42 at the other end. A packer pressure line 44 is connected at one end to a pressure supply (not shown) and to packer 36 by a packer pressure inlet 38 at the other end.

Alternative configurations of the reinforcing member which can be positioned in the pile as shown in FIG- URES 1 and 2 are s t forth in FIGURES 3a, 3b, 3c, and 3d. Also alternative means for securing the reinforcing member in the piles as shown in FIGURES 1 and 2 are set forth in FIGURES 4a, 4b, and 40.

In FIGURE 3a a corrugated tubular reinforcing member 12 is shown positioned inside a pile 10. The corrugated member can be easily expanded into frictional engagement in the same manner as shown in FIGURES 1 and 2.

FIGURE 3b shows a pile 10 having a corrugated tubular member 50 and a corrugated tubular member 52 interconnected by a plurality of steel webbs 54. This configuration is expanded as is shown in FIGURES 1 and 2 so that a double layer of reinforcing material is present.

FIGURE 30 shows a pile 10 having a series of wedgeshaped members 56 positioned adjacent the interior wall of pile and a second series of wedge-shaped members 58 positioned inside said wedge-shaped members 56. M mbers 58 are forced between members 56 by the expanding action as shown by FIGURES l and 2.

FIGURE 3d shows a pile 10 having a tubular reinforcing member 60 placed therein.

FIGURE 4a shows a portion of a pile 10 and a portion of a reinforcing member 12 rigidly connected thereto by a cement 62.

FIGURE 4b shows a portion of a pile 10 and a portion of a reinforcing member 12 rigidly connected thereto by a weld 66.

FIGURE 40 shows a portion of a pile 10 and a portion of a reinforcing member 12 rigidly connected thereto by a metal fastener 68.

Operation In FIGURE 1, which represents the preferred embodiment, a cylindrical tubular pile 10 is strengthened by placing a tubular reinforcing member 12 within said pile at the position to be strengthened, normally at the mud line. Pump 26 applies pressure through pressure outlet to piston 18 located within pressure chamber 15. As pressure is applied to piston 18, said piston is moved upwardly within pressure chamber 15. The upward movement of piston 18 causes xpander mandrel 14- to be advanced through tubular reinforcing member 12 so as to expand said member to form expanded reinforcing member and frictionally engaged member 32. As expander mandrel 14 is advanced through said reinforcing member 12, frictionally engaged member 32 increases in size until all of reinforcing member 12 becomes frictionally engaged member 32. Hold down plate 16 is positioned within pile 10 prior to the advancement of expander mandrel 14 so as to engage reinforcing member 12 to prevent said reinforcing member 12 from being ejected from pile 10 as expander mandrel 14 is advanced through reinforcing member 12. Sump 28 connects pump 26 with pressure outlet 22 and suction from pump 26 through said sump and pressure outlet helps lift piston 18 to advance expander mandrel 14. Support member 24 connects pressure chamber 15 with a derrick or crane (not shown) which is used to raise and lower said pressure chamber and other ancillary equipment into the desired position within pile 10.

In FIGURE 2, a pile 10 is strengthened by placing a tubular reinforcing member 12 within said pile at the position to be strengthened, normally at the mud line. Rotary drive means (not shown), said means being well-known in the art, is conn cted to tube roller 46 by rotary drive shaft 41 and rotary drive shaft extension so as to impart rotary motion to tube roller 46. Said rotary drive means is also used to advance tube roller 46 upwardly through tubular reinforcing member 12, said upward advancement technique being well-known in the art; i.e., normal rotary drilling mechanisms used in oil well drilling. As tube roller 46 is rotated and advanced upwardly reinforcing member 12 is rolled so as to form expanded reinforcing member 30 and frictionally engaged member 32. Said process is continued until reinforcing member 12 is transformed substantially into frictionally engaged member 32 throughout its entire length. Packer 36 is positioned so as to engage reinforcing member 12 to prevent its ejection from said pile 10 and to prevent rotation of said reinforcing member 12 during the rolling operation. Packer 36 receives pressure from a pressure source (not shown) through packer pressure line 44 and packer pressure inlet 38 so as to expand packer 36 into rigid engagement with the interior walls of pile 110. Packer 36 is equipped with a bearing 34 so as to allow stabilized rotary motion of rotary drive shaft 41.

It will be obvious to those skilled in the art that many other changes and modifications of the invention may be made without departing from the true scope thereof as defined in the appended claims.

What is claimed is:

1. A method of strengthening a cylindrical tubular foundation pile at a point of localized strcss while said pile is positioned in the ground, comprising:

(a) positioning a tubular reinforcing member at a point of localized stress inside said pile; and

(b) expanding said tubular reinforcing member into frictional engagement with the interior walls of said pile.

2. The method of claim 1 wherein said tubular reinforcing member is expanded by rolling the internal walls of said tubular reinforcing member so that the exterior walls of said tubular reinforcing member is in frictional engagement with the interior walls of said foundation pile.

3. A method of strengthening a cylindrical tubular foundation pile at a point of localized stress while said pile is positioned in the ground, comprising:

(a) positioning a reinforcing member at a point of localized stress inside said pile; and

(b) rigidly securing said reinforcing member in place.

4. The method of claim 3 wherein said reinforcing member is secured in place by mechanically fast ning said reinforcing member to said pile at a plurality of locations.

5. The method of claim 4 wherein the reinforcing member is mechanically fastened by fusing the edge of said reinforcing member to the interior Walls of said pile.

6. A method of strengthening a cylindrical tubular foundation pile at a point of localized stress while said pile is positioned in the ground, comprising:

(a) placing a plurality of Wedge-shaped sections of sufiicient length within said pile and at a point of localized stress to strengthen said pile at said position, said wedge-shaped sections being placed so as to line the interior wall of said pile;

(b) placing a second plurality of wedge-shaped sections within said first placed sections, said second sections being positioned so as to spread said first placed sections into engagement with the interior wall of said pile upon applying outward pressure to said second placed sections; and

(c) applying outward pressure upon said second placed sections so as to engage said second placed sections with said first placed sections.

7. The method of claim 6 wherein said outward pressure is applied by rolling said wedge-shaped sections into rigid engagement with the interior walls of said pile.

8. The method of claim 1 wherein the point of localized stress is at the mud line.

9. The method of claim 3 wherein the reinforcing member is secured in place with a cement selected from the group consisting of a high-tensile strength epoxy resin, resin cement and glue.

References Cited UNITED STATES PATENTS 1,081,496 12/1913 Gillmor 29523 X 1,166,038 12/1915 Burlingharn 29523 2,435,837 2/1948 Larson 29-523 2,898,971 8/1959 Hempel 29-523 X JACOB SHAPIRO, Primary Examiner. 

